An arrangement in which a so-called BBW (brake-by-wire) type brake device, in which a driver's braking operation is converted into an electrical signal so as to operate a slave cylinder and a wheel cylinder is operated by a brake fluid pressure generated by this slave cylinder, is combined with an ABS (antilock brake system) system that suppresses locking of a wheel so as to shorten the braking distance is known from Patent Document 1 below.    Patent Document 1: Japanese Patent Application Laid-open No. 2007-326395